C＃从Form2中选择Form1中的文本

Question

Okay, so I have my main form ( Form1 ) and SearchReplace form. My SearchReplace form contains a textbox and a button. When the button is pressed, it is supposed to select whatever was in the textbox in Form1 , but just does nothing. Can anyone help me? Not throwing me an error, just not doing anything runtime.

SearchReplace

    public void button1_Click(object sender, EventArgs e)
    {
        Form1.searchT = textBox1.Text;


        Form1 form1 = new Form1();
        form1.searchText();
        this.Close();
    }

Form1 searchText

    public void searchText() // search function
    {

        if (searchT != null)
        {
            if (textBox1.TextLength > 0)
            {
                if (textBox1.Text.Contains(searchT))
                {
                    textBox1.SelectionStart = textBox1.Text.IndexOf(searchT);
                    textBox1.SelectionLength = searchT.Length;
                }
            }
        }
    }

searchT is a public string created in Form1 because when I asked perviously about passing data from one form to another, someone informed me that it was easier to do it directly through Form1 instead using the form1 object.

Answer 1

Based in your recent comment it's best to hide your current form (SearchReplace) before calling Form1. And then close it once Form1 also is closed. Check my code below:

Let's say this is your SearchReplace form:

public partial class SearchReplace : Form
{
    Form1 form1;

    public SearchReplace()
    {
        InitializeComponent();
    }

    void form1_FormClosed(object sender, FormClosedEventArgs e)
    {
        this.Close(); // When form1 is closed then close also SearchReplace form
    }

    private void button1_Click(object sender, EventArgs e)
    {

        Form1.searchT = textBox1.Text; // assign textbox1 to searchT
        form1 = new Form1(); // instantiate first
        form1.FormClosed += new FormClosedEventHandler(form1_FormClosed); // When Form1 Close
        form1.searchText(); // Run searchText function
        form1.Show(); // Show Form1
        this.Hide(); // Make SearchReplace form invisible but still in memory
    }
}

And your Form1 would be like:

public partial class Form1 : Form
{
    public static string searchT; // Static searchT string as per your requirement

    public Form1()
    {
        InitializeComponent();
    }


   public void searchText() // search function
   {

    if (searchT != null)
    {
        if (textBox1.TextLength > 0)
        {
            if (textBox1.Text.Contains(searchT))
            {
                textBox1.SelectionStart = textBox1.Text.IndexOf(searchT);
                textBox1.SelectionLength = searchT.Length;
            }
        }
    }
  }    
}

Answer 2

The problem is that you're creating an entirely new Form on the button click. You should be able to accomplish what you want with just this:

public void button1_Click(object sender, EventArgs e)
{
    Form1.searchT = textBox1.Text;
    searchText(); //Calls this instance's searchText() function
    this.Close();
}

You might want to make searchT non-static, otherwise its value will apply to all instances of Form1 .

Answer 3

You can pass a reference to the textbox in form1 to the constructor of form searchreplace. Then use this reference to select the given text.

Answer 4

Depending how you create your SearchReplace Form you can assign Form1 as the Owner by using the Show or ShowDialog Method that allows you to set the owning form, then instead of relying on setting a variable in Form1 just pass the parameter to your Function. Something like this should work for you.

Form1

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    public void searchText(string searchT) // search function
    {

        if (searchT != null)
        {
            if (textBox1.TextLength > 0)
            {
                if (textBox1.Text.Contains(searchT))
                {
                    textBox1.Focus(); // put focus to the Textbox so we can see our selection
                    textBox1.SelectionStart = textBox1.Text.IndexOf(searchT);
                    textBox1.SelectionLength = searchT.Length;

                }
            }
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        SearchReplace sr = new SearchReplace(); // Creating your SearchReplace Form
        sr.Show(this);  // Pass the creating form in as the Owner
    }
}

SearchReplace Form

public partial class SearchReplace : Form
{
    public SearchReplace()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        ((Form1)this.Owner).searchText(textBox1.Text); //Cast the Owner to Form1 and access the Function 
                                                       //passing in your search Parameter
        this.Close();
    }
}

Answer 5

There's nothing wrong with your code, except that you only declare which text will be selected, don't expect it to automatically highlight, I suggest you change the backgroundcolor or the selected text to highlight it. try my example.

and I SUGGEST that you use RichTextBox

in your Form1 is suppose you declare a

public static string searchT;

then in your Form1 show the searchReplace form as a Dialog

        private void searchReplaceBtn_Click(object sender, EventArgs e)
        {
            Form2 frm = new Form2();
            if (frm.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                searchText();
            }
        }

then in your SearchReplace Form

        private void button1_Click(object sender, EventArgs e)
        {
            Form1.searchT = textBox1.Text;
            this.DialogResult = System.Windows.Forms.DialogResult.OK;
        }

finally in your searchtext Method

        private void searchText()
        {

            if (searchT != null)
            {
                if (textBox1.TextLength > 0)
                {
                    int index = 0;
                    //this will loop through the entire richTextBox
                    while (index < textBox1.Text.LastIndexOf(searchT))
                    {
                        //this will select the text that matches the searchT
                        textBox1.Find(searchT, index, textBox1.TextLength, RichTextBoxFinds.None);
                        //this will change the background color of each of the selected text
                        textBox1.SelectionBackColor = Color.Yellow;
                        //this will continue searching to the end of the text
                        index = textBox1.Text.IndexOf(searchT, index) + 1;
                    }
                }
            }
        }

NOTE: you can't select multiple text in textbox, that's why changing the backcolor of each of the text that matches your searchT will be the best option.

Hope this helps :)

Answer 6

you can do this one by using a property and giving the value of that certain textbox.

In your form1:

public static string Text
{
   get { return textbox1.Text; }
}

And you can get it at your other form by

form1.Text;